2.5–15 mg/70 kg of body weight in 4–5 mL water for injection administered over 4–5 min, or as directed by physician. Continuous IV infusion: 0.1–1 mg/mL in D5W by controlled infusion device.

Rectal

10–30 mg q 4 hr or as directed by physician.

Epidural

Initial injection of 5 mg in the lumbar region may provide pain relief for up to 24 hr. If adequate pain relief is not achieved within 1 hr, incremental doses of 1–2 mg may be given at intervals sufficient to assess effectiveness, up to 10 mg/24 hr. For continuous infusion, initial dose of 2–4 mg/24 hr is recommended. Further doses of 1–2 mg may be given if pain relief is not achieved initially.

Liposome injection

10–15 mg by lumbar epidural injection using a catheter or needle prior to major surgery or after clamping the umbilical cord during cesarean section.

Intrathecal

Dosage is usually one-tenth that of epidural dosage; a single injection of 0.2–1 mg may provide satisfactory pain relief for up to 24 hr. Do not inject > 2 mL of the 5 mg/10 mL ampule or > 1 mL of the 10 mg/10 mL ampule. Use only in the lumbar area. Repeated intrathecal injections are not recommended; use other routes if pain recurs. For epidural or intrathecal dosing, use preservative-free morphine preparations only.

PEDIATRIC PATIENTS

Do not use in premature infants.

IM or subcutaneous

0.05–0.2 mg/kg (up to 15 mg per dose) q 4 hr or as directed by physician.

GERIATRIC PATIENTS OR IMPAIRED ADULTS

Use caution. Respiratory depression may occur in the elderly, the very ill, those with respiratory problems. Reduced dosage may be needed.

Epidural

Use extreme caution; injection of < 5 mg in the lumbar region may provide adequate pain relief for up to 24 hr.

Intrathecal

Use lower dosages than recommended above for adults.

Therapeutic actions

Morphine is a phenanthrene derivative which acts mainly on the CNS and smooth muscles. It binds to opiate receptors in the CNS altering pain perception and response. Analgesia, euphoria and dependence are thought to be due to its action at the mu-1 receptors while respiratory depression and inhibition of intestinal movements are due to action at the mu-2 receptors. Spinal analgesia is mediated by morphine agonist action at the K receptor. Cough is suppressed by direct action on cough centre.

WARNING: Keep opioid antagonist and facilities for assisted or controlled respiration readily available during IV administration.

WARNING: Use caution when injecting IM or subcutaneously into chilled areas or in patients with hypotension or in shock; impaired perfusion may delay absorption; with repeated doses, an excessive amount may be absorbed when circulation is restored.

Reassure patients that they are unlikely to become addicted; most patients who receive opiates for medical reasons do not develop dependence syndromes.

BLACK BOX WARNING: Liposome preparation is for lumbar epidural injection only; it should not be given intrathecally, IV, or IM.